Robert Ford, the US ambassador to Syria who has been Washington’s main pointman in efforts to end the war working with opposition leaders battling President Bashar al-Assad, stepped down.

“Robert Ford is retiring from the foreign service on Saturday after nearly 30 years of distinguished service,” State Department spokeswoman Jen Psaki said.

She admitted that the departure of Ford, who over the past three years has built up extensive contacts with the opposition leaders and was instrumental in helping to bring them to the Geneva peace talks, would be a loss.

“His extraordinary leadership has guided our response to one of the most formidable foreign policy challenges in the region,” Psaki said.

“From the outbreak of the crisis, Ambassador Ford has worked tirelessly in support of the Syrian people in their pursuit of freedom and dignity.”

A fluent Arabic speaker, Ford became Washington’s first ambassador to Damascus in five years when he was named in late 2010.

But just a few months into his post, Ford was abruptly pulled out of the country in October 2011 amid fears for his safety when he became a vocal critic of the Assad regime and its crackdown on the pro-democracy uprising that erupted in March that year. He never returned full-time to Syria.

Ford was increasingly criticised by the regime, which accused him of helping incite violence and was angered when he visited protest hubs outside the capital in a show of solidarity with pro-democracy demonstrators.

In late September 2011, Ford was blocked inside a building for a few hours during a meeting with opposition member Hassan Abdel Azim when nearly 100 angry pro-regime protesters tried to storm the offices.

Washington decided to close the embassy in 2012 as the uprising descended swiftly into a bloody civil war.

Since then, Ford has shuttled between the United States and Turkey, spending hours huddled with opposition leaders based out of Istanbul as he sought to help them form a more cohesive and inclusive body.